Vehicles, e.g., automobiles, generally have four wheels; i.e., two front wheels and two rear wheels, and can have an electronic control device for driving the wheels.
Japanese Laid-open Patent Application (JP-A) No. 2006-256605 discloses a four-wheel-drive electronic control unit (4WD-ECU) as such an electronic control device. The 4WD-ECU disclosed in JP 2006-256605 A together with a vehicle stability assist (VSA)-ECU controls the drive force that operates on the vehicle, and specifically determines, e.g., the torque as units.
In this manner, a 4WD-ECU operates in coordination with the VSA-ECU and controls the drive force. Specifically, the VSA-ECU can request the 4WD-ECU to limit the drive force in the case that, e.g., the traveling state of the vehicle is unstable. The 4WD-ECU can reduce the drive force and improve vehicle stability in response to a request from the VSA-ECU.
A VSA-ECU or other vehicle behavior control means can generally be provided with at least one function from among a function for suppressing spinning of wheels (traction control system), a function for suppressing locking of wheels (antilock brake system), and a function for suppressing side-slipping of a vehicle.